data we got was only the NUMBER of pieces of trash, not the WEIGHT.
This is the tricky part about graphs, and science in general. You
have to be very careful about what you think is true, or assume, before
What if instead of counting the number of
pieces of trash, the students weighed the trash? Would the data
look different? Probably so. Metal generally weighs much more
than the other materials, and cigarette butts weigh very little.
How would this change the appearance of the graph? It's a good bet
that cigarettes would have a much smaller pie piece, and metal would have
a much bigger piece.